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Diffstat (limited to 'lib/fsusage.c')
| -rw-r--r-- | lib/fsusage.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/lib/fsusage.c b/lib/fsusage.c new file mode 100644 index 0000000..8196015 --- /dev/null +++ b/lib/fsusage.c @@ -0,0 +1,237 @@ +/* fsusage.c -- return space usage of mounted file systems + + Copyright (C) 1991-1992, 1996, 1998-1999, 2002-2006, 2009-2020 Free Software + Foundation, Inc. + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. */ + +#include <config.h> + +#include "fsusage.h" + +#include <limits.h> +#include <sys/types.h> + +#if STAT_STATVFS || STAT_STATVFS64 /* POSIX 1003.1-2001 (and later) with XSI */ +# include <sys/statvfs.h> +#else +/* Don't include backward-compatibility files unless they're needed. + Eventually we'd like to remove all this cruft. */ +# include <fcntl.h> +# include <unistd.h> +# include <sys/stat.h> +#if HAVE_SYS_PARAM_H +# include <sys/param.h> +#endif +#if HAVE_SYS_MOUNT_H +# include <sys/mount.h> +#endif +#if HAVE_SYS_VFS_H +# include <sys/vfs.h> +#endif +# if HAVE_SYS_FS_S5PARAM_H /* Fujitsu UXP/V */ +# include <sys/fs/s5param.h> +# endif +# if HAVE_SYS_STATFS_H +# include <sys/statfs.h> +# endif +#endif + +/* Many space usage primitives use all 1 bits to denote a value that is + not applicable or unknown. Propagate this information by returning + a uintmax_t value that is all 1 bits if X is all 1 bits, even if X + is unsigned and narrower than uintmax_t. */ +#define PROPAGATE_ALL_ONES(x) \ + ((sizeof (x) < sizeof (uintmax_t) \ + && (~ (x) == (sizeof (x) < sizeof (int) \ + ? - (1 << (sizeof (x) * CHAR_BIT)) \ + : 0))) \ + ? UINTMAX_MAX : (uintmax_t) (x)) + +/* Extract the top bit of X as an uintmax_t value. */ +#define EXTRACT_TOP_BIT(x) ((x) \ + & ((uintmax_t) 1 << (sizeof (x) * CHAR_BIT - 1))) + +/* If a value is negative, many space usage primitives store it into an + integer variable by assignment, even if the variable's type is unsigned. + So, if a space usage variable X's top bit is set, convert X to the + uintmax_t value V such that (- (uintmax_t) V) is the negative of + the original value. If X's top bit is clear, just yield X. + Use PROPAGATE_TOP_BIT if the original value might be negative; + otherwise, use PROPAGATE_ALL_ONES. */ +#define PROPAGATE_TOP_BIT(x) ((x) | ~ (EXTRACT_TOP_BIT (x) - 1)) + +#ifdef STAT_STATVFS +/* Return true if statvfs works. This is false for statvfs on systems + with GNU libc on Linux kernels before 2.6.36, which stats all + preceding entries in /proc/mounts; that makes df hang if even one + of the corresponding file systems is hard-mounted but not available. */ +# if ! (__linux__ && (__GLIBC__ || __UCLIBC__)) +/* The FRSIZE fallback is not required in this case. */ +# undef STAT_STATFS2_FRSIZE +static int statvfs_works (void) { return 1; } +# else +# include <string.h> /* for strverscmp */ +# include <sys/utsname.h> +# include <sys/statfs.h> +# define STAT_STATFS2_BSIZE 1 + +static int +statvfs_works (void) +{ + static int statvfs_works_cache = -1; + struct utsname name; + if (statvfs_works_cache < 0) + statvfs_works_cache = (uname (&name) == 0 + && 0 <= strverscmp (name.release, "2.6.36")); + return statvfs_works_cache; +} +# endif +#endif + + +/* Fill in the fields of FSP with information about space usage for + the file system on which FILE resides. + DISK is the device on which FILE is mounted, for space-getting + methods that need to know it. + Return 0 if successful, -1 if not. When returning -1, ensure that + ERRNO is either a system error value, or zero if DISK is NULL + on a system that requires a non-NULL value. */ +int +get_fs_usage (char const *file, char const *disk, struct fs_usage *fsp) +{ +#ifdef STAT_STATVFS /* POSIX, except pre-2.6.36 glibc/Linux */ + + if (statvfs_works ()) + { + struct statvfs vfsd; + + if (statvfs (file, &vfsd) < 0) + return -1; + + /* f_frsize isn't guaranteed to be supported. */ + fsp->fsu_blocksize = (vfsd.f_frsize + ? PROPAGATE_ALL_ONES (vfsd.f_frsize) + : PROPAGATE_ALL_ONES (vfsd.f_bsize)); + + fsp->fsu_blocks = PROPAGATE_ALL_ONES (vfsd.f_blocks); + fsp->fsu_bfree = PROPAGATE_ALL_ONES (vfsd.f_bfree); + fsp->fsu_bavail = PROPAGATE_TOP_BIT (vfsd.f_bavail); + fsp->fsu_bavail_top_bit_set = EXTRACT_TOP_BIT (vfsd.f_bavail) != 0; + fsp->fsu_files = PROPAGATE_ALL_ONES (vfsd.f_files); + fsp->fsu_ffree = PROPAGATE_ALL_ONES (vfsd.f_ffree); + return 0; + } + +#endif + +#if defined STAT_STATVFS64 /* AIX */ + + struct statvfs64 fsd; + + if (statvfs64 (file, &fsd) < 0) + return -1; + + /* f_frsize isn't guaranteed to be supported. */ + fsp->fsu_blocksize = (fsd.f_frsize + ? PROPAGATE_ALL_ONES (fsd.f_frsize) + : PROPAGATE_ALL_ONES (fsd.f_bsize)); + +#elif defined STAT_STATFS3_OSF1 /* OSF/1 */ + + struct statfs fsd; + + if (statfs (file, &fsd, sizeof (struct statfs)) != 0) + return -1; + + fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize); + +#elif defined STAT_STATFS2_FRSIZE /* 2.6 < glibc/Linux < 2.6.36 */ + + struct statfs fsd; + + if (statfs (file, &fsd) < 0) + return -1; + + fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_frsize); + +#elif defined STAT_STATFS2_BSIZE /* glibc/Linux < 2.6, 4.3BSD, SunOS 4, \ + Mac OS X < 10.4, FreeBSD < 5.0, \ + NetBSD < 3.0, OpenBSD < 4.4 */ + + struct statfs fsd; + + if (statfs (file, &fsd) < 0) + return -1; + + fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_bsize); + +# ifdef STATFS_TRUNCATES_BLOCK_COUNTS + + /* In SunOS 4.1.2, 4.1.3, and 4.1.3_U1, the block counts in the + struct statfs are truncated to 2GB. These conditions detect that + truncation, presumably without botching the 4.1.1 case, in which + the values are not truncated. The correct counts are stored in + undocumented spare fields. */ + if (fsd.f_blocks == 0x7fffffff / fsd.f_bsize && fsd.f_spare[0] > 0) + { + fsd.f_blocks = fsd.f_spare[0]; + fsd.f_bfree = fsd.f_spare[1]; + fsd.f_bavail = fsd.f_spare[2]; + } +# endif /* STATFS_TRUNCATES_BLOCK_COUNTS */ + +#elif defined STAT_STATFS2_FSIZE /* 4.4BSD and older NetBSD */ + + struct statfs fsd; + + if (statfs (file, &fsd) < 0) + return -1; + + fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_fsize); + +#elif defined STAT_STATFS4 /* SVR3, old Irix */ + + struct statfs fsd; + + if (statfs (file, &fsd, sizeof fsd, 0) < 0) + return -1; + + /* Empirically, the block counts on most SVR3 and SVR3-derived + systems seem to always be in terms of 512-byte blocks, + no matter what value f_bsize has. */ +# if defined _CRAY + fsp->fsu_blocksize = PROPAGATE_ALL_ONES (fsd.f_bsize); +# else + fsp->fsu_blocksize = 512; +# endif + +#endif + +#if (defined STAT_STATVFS64 || defined STAT_STATFS3_OSF1 \ + || defined STAT_STATFS2_FRSIZE || defined STAT_STATFS2_BSIZE \ + || defined STAT_STATFS2_FSIZE || defined STAT_STATFS4) + + fsp->fsu_blocks = PROPAGATE_ALL_ONES (fsd.f_blocks); + fsp->fsu_bfree = PROPAGATE_ALL_ONES (fsd.f_bfree); + fsp->fsu_bavail = PROPAGATE_TOP_BIT (fsd.f_bavail); + fsp->fsu_bavail_top_bit_set = EXTRACT_TOP_BIT (fsd.f_bavail) != 0; + fsp->fsu_files = PROPAGATE_ALL_ONES (fsd.f_files); + fsp->fsu_ffree = PROPAGATE_ALL_ONES (fsd.f_ffree); + +#endif + + (void) disk; /* avoid argument-unused warning */ + return 0; +} |